Air bag



March s,19z7. 1,620,435

R. S. BURDETTE AIR BAG Filed May 23, 1925 3 Sheets-Sheet l "lll" um I/ATTORNEY March 8,1927. A i A R. S'BURDETTE 62o 43s AIR BAG Filed May 23.1925 5 Sheets-Sheet 2 ATTORNEY March 8, 1927.

R. S. BURDETTE AIR BAG Fild mayl 2s, 1925 3 Siheets-Sheet 3 -gNvENTc-JRHome@ 3u/ewa- ATTORNEY Patented Mar. 8, 1927.

UNITED STATES PATENT OFFICE.

RICHARD S. BURDETTE, OF AKRON, OHIO, ASSIGNOR T0 THE GOODYEAR TIRE &

RUBBER COMPANY, OF AKRON, OHIO, A CORPORATION OF OHIO. l

AIR BAG.

Appiication mea 'may 2s, 1925. seriai No. 32,389.

My invention relates to cores employed in vulcanization of pneumatictire casmgs and it has particular relation to cores of the in` flatabletype suitable for use iii repairing such easings.

One object of my invention consists in providing a novel type ofvulcanizing core which is constructed of a relatively small amountof'flexible material which depends upon its flexing' qualities ratherthan its resilient qualities to conform to the shape of a tire casingbeing repaired.

Another object of my invention is to provide a exible fluid containerwhich is so arranged upon a supporting member that it is equally welladapted for use as a vulcanizing core in varioussizes and types of tirecasings.

Another object of my invention is to provide a vulcanizing core whichreduces to a minimum the deteriorating stresses caused by fluid pressureexerted uponthe internal walls of a flexible bag forming a part of thecore.

Another object of my invention consists inproviding a vulcanizing corein which fluid pressure is employed and which is so constructed that arelatively small volume of fluid suffices to produce a maximum amount ofpressure against a tire casing.

A further object of my invention consists in providing a vulcanizingcore composed of replaceable rigid members and a replaceable inflatableflexible portion, which members and portion are adapted to be quicklyassembled or dismantled.

My invention was developed particularly with a view to improvingvulcanizing, cores in which so-called airbags are employed.

4 In the repair of pneumatic casings it is necessary to vulcanize theuncured rubberused in the repair in order to give to the -repairedportion a toughness and strength comparable with the other portions ofthe casing. In vulcanizing a tire casing, the defective portions areremoved, raw rubber or rubber and fabric is inserted in place thereof,and the repaired casing is placed within a heated metallic mold having a.'.e cess which conforms to the contour of the outer surface of thecasing. Within the casing is inserted an inflatable pneumatic core orairbag which is of substantially the saine diameter as the innerperiphery of the ydirections when subjected to inflation under highpressure. One objection to this type of airbag has been that, althoughthe walls of the bag are reinforcedby contact Wit-h the inner surface ofthe tire casing and are not subjected to any injurious stresses uponthis surface, nevertheless the end ,portions thereof are totallyunsupported and are subjected to the same pressure as the contactingwalls of the airbag. As thepressure necessary to properly cure andrepair the casing is reasonably high, the total force developed in anairbag of large diameter, such as a truck tire or balloon tire bag, isvery great. This being true, it is necessary to reinforce the ends ofthe airbags by the addition of layers of reinforcing material in orderto preventinjury to the bags. Also, in order to provide proper anchoragefor these reinforcing ends, it is necessary toconstruct the side WallsofV heavier material thanA would otherwise be required.

Another objection of this type of bag is that', owing to the differencein length of the outer periphery and the inner periphery of the bag andthe fact that the ends thereof are disposed at a considerable angle toeach other, certain unbalanced stresses are produced therein which tendto deform the bag excessively adjacent the bead portions of the tirecasing.v A still further objection to this type of bag is that, as thebag is unitary, when one portion thereof fails, the entire bag isrendered useless.

By my invention I have obviated these lobjections by providing arelatively large supporting member for supporting an airbag against atire which substantially eliminates the undesirable effects ofunbalancedforces developed in the bag, thereby reducing the strain imposed uponthe end of the bag when a sectional bag is employed and necessitatinonly a small volume of fluid to obtain re atively high pressure.

For a more thorough description of my invention, reference may now behad to the accompanying drawings forming a part of this specification,and in Which:

Fig. 1 is a fragmentary view of a tire mold and a tire casin used inconjunction with one application o my invention;

Fie. 2 is a. cross-sectional view taken along the line II--II of Fig. lshowing an airbag and a su orting member therefor Within a tire mo d)constructed in accordance with my invention;

Fig. 3 is a perspective view of a rigid core upon which an airbag isadapted to be mounted;

Fig. 4 is a fragmentary view of a tire mold similar to that illustratedin Fig. ,1, showing an application of my invention 1n modified form;

Fig. 5 is a cross-sectional view showing a securing bracket supportinga. tire in a mold, the view being taken along the line V-V of Fig. 4;

Fig. 6 is a view in detail of a core used in the embodiment of myinvention as shown in Figs. 4 and 5;

Fig. 7 is a view in detail of a modified form of construction of thebracket member shown in Fig. 5;

Fig. 8 is a cross-sectional view of an airbag constructed in accordancewith my invention;

Fig. 9 is a cross-sectional View of an airbag in the first stages ofmanufacturing before fabric is applied thereto; l

Fig. 10 is a perspective vievv7 of a full circle airbag constructed inaccordance with my invention; and

Fig. 11 is a view on an enlarged scale of a portion of an airbagillustrating the manner in which the airbag is reinforced about thevalve connection thereof.

In practicing my invention, and referring to the embodiment thereofillustrated in Figs. 1, 2, and 3, I have provided a core 20 consistingof arcuate sections :ll preferably composed of rigid material, such asivoo the sections thereof being adapted to be constructed in the form ofan annulus or 1/3 or /L circles. Sections of the core are retained upona ring 23 and are provided With fittings. as indicated at 24. whichprevent relative lateral displacement and insure a snug tit between theends of the respective sections. the core is substantially peaushaped incross-section and is provided with an outer peripheral surface "25 whichsubstantially conforms to the shape of the inner surface ot' a tirecasing 26. n

On the outer peripheral surface of the. core, I have provided a flexiblesleeve or It will be observed thatenvelope si, which, according to theembodiment of my invention, as illustrated in Figs. l to 3 and 10, ispreferably in the form of an endless flexible tube of substantiallycrescent-shape in cross-section and so 27 mounted upon the core isdisposed Wit in the tire casing 26 and engages a portion of the casing.adjacent the tr'ead2 which is to be repaired. The 'space occupied by theenvelope between the core and the surface of the casing is very'narrowand approximately of crescent-shape in cross-section. Oppositelydisposed folds 30 of the envelope are adapted to flex against thesurface of the core and the adjacent surface of the casing when fluid isadmitted into the envelope under pressure. As shown in the drawings thedistance between the surface of the core and the adjacent surface of thetire casing appears to be considerable, but this is an exaggerated viewand is illustratcd in this manner for the sake of clearness. In actualpractice, the distance be tween these surfaces is very slight.

A small amount of fluid is introduced within the envelope Q7 in orderthat it may engage the casing with enough force to maintain it inoperative position and it is placed within a mold 3l of conventionaltype formed of several sections 32 as best shown in Fig. l. Adjacent theopposed ends of the respective sections of the mold, I have providedlugs 33 adapted to receive bolts 34 pivoted thereto, the latter heiligadapted to swing into engagement with slotted lugs 35 and to be held inplace by nuts 36. By utilizing this structure, i't will be observed thatthe mold may be, adjusted to receive various sizes ol' tire casings.Each section of the mold is provided with an inlet valve connection 3Tand an outlet valve connection 38, which permit of circulation of aheating fluid within a heating chamber in the form of a hollow portionof the mold, as indicated at 3S), which is disposed adjacent. the treadportion of the casing while it is beingrepaired.

Al'ter the casing' is placed in die mold, the latter is adjusted toconform to the size of the iirc casingl and fluid under lncssure isadmitted through the valve 2S until the desired pressure is attainedagainst the inner surface of the casing. L'pon the introduc tion offluid through the valve 28, the folds occupying the narrow space betweenthe core and the casing, are subjected to relatively little sressbecausethe force is primarily imposed upon the surface 25 of the core and theoppositcly disposed portion of the casing. In fact the reduction ofintensity ot' the stresses caused by this arrangement is so marked thatutilization of envelopes composed of relative small amounts of materialis made possible without reducing the amount of pressure against therepaired portion of the casing. Also, it will be observed that the beadsof the casing are free from engagement with any part of the pressurearea and cannot be damaged by deformation of the envelope or airbagagainst them.

Referring now to Figs. 4, 5, and 6, it will be observed that. anenvelope 40, substan- Vtially of crescent-shape in cross-section, isprovided with folds 41 similar to the structure shown in Fig. Q. Theenvelope is also provided with a valve connection 42, but the envelopeor bag in this case is in the form of a sectorof an annulus and it isdisposed on an arcuate metal support 43. The metal supporting member iscomposed of sections which are held in abutting relationship, asindicated at the joint 44. In order to accommodate the valve 42, anopening 45 is provided through the support 43 and is adapted to receivethe valve therethrough. A convex surface 46 is also formed on thesupport .43

similar to the surface Q5. above described, and is adapted to supportthe envelope in exactly the same manner as the core 520 supports theenvelope 27.

In this embodiment of my invention, I have employed a mold 47 inonesection provided with an inlet valve connection 48 and an outlet valveconnecfion 49, each of which communicates with a heating chamber 50.When the metal support 43 with the envelope mounted thereon is disposedwithin the casing, U-shaped brackets 52, having arms 53 and projectingmembers 54, are arranged to engage the metal support. The arms of thebracket which are provided with lugs 55 are hooked over flanges 56 uponthe mold, thereby retaining the core, `tire and mold in assembledrelationship.

lVhen fluid under pressure is admitted to the envelope 42, each of thefolds 41 thereof flex between the surface of the metal support and thesurface of the casing 26, while the end portions. indicated at 57, flexin substantially the same manner longitudinally of the metal support.

As a modification' of the projecting member 53, I have shown in Fig. 7 ascrew threaded bolt 5S adapted to be adjusted within the screw threadedopening 59 provided in the U-shape member' 52, the upper end of the boltbeing adapted to engage the shown in Fig. 11.

inner periphery of the metal support 43. A lock nut (S0 is provided forthe purpose of securing the bolt in adjusted position. ,By thisconstruction the peripheral surface of the supporting member 43 may bebrought as closely as desired to the inner periphery of the tire casingbefore the fluid under pressure is admitted to the envelope. l

In order to have a thorough understanding of the preferred method ofconstructing an envelope or airbag suitable for use in connection withthe practice of my invention, reference may now be had to Figs. 8 to 1l.In these figures, I have shown a bag or impervious container 62 composedof vulcanizable material, such as rubber, which is provided with one ormore layers of cord fabric 63 wound transversely about the container insuch manner that the cords will resist any tendency toward crosswiseexpansion of the container. A suitable valve connection 64 is insertedthrough the wall of the container and is reinforced by means of .aplruality of fabric strips (35, as clearly After ,the cords are woundtransversely about theV container, one or more layers of cross-wovenfabric 66 are applied, which extend about the portion of the. envelopethat is adapted to rest upon a supporting core.

Each edge of the cross-woven fabric, as indicated at 67, extends overthe sides of the envelope a sufficient distance to include the foldedportions, which are clearly indicated at 30 and 41 in Figs. 2 and 5,respectively'.

In the form shown in Fig. 8, the rubber` container, the cords and fabricare vulcanized together, thus providing an envelope or airbag which willexpand longitudinally when such expansion is necessary, but which isprevented from transverse expansion by reason of the transverselyarranged inerttensible cords incorpo 'ated therein. Airbags constructedas above described may be made in full circle formation, as shown inFig. 10, or in segment formation, as shown in Fig. 4.

From the foregoing description, it will be apparent that I have provideda novel type of Vulcanizing core in which stresses are so reduced anddistributed that relatively high .pressure may be employed withoutIdetriment to a bag colnposcd of a relatively small quantity of lightweight fabric or cords.

Thei narrower the space between the core and the opposing surface of thetire casing, the less will be the stress imposed upon the airbag. Itwill also be apparent that by obviating unbalanced forces and byreducing the stretching properties of the bag to a minimum, the life ofthe bag will be nxate rially prolonged. Moreover, the possibility ofinjury to the casing being cured b v the llO airbag will be obviated. Itwill be further apparent that the life ofthe bag of the characte-rdescribed will be greater ,than that of the old type of bag because thethinner walls may be subjected to flexing with less injury thereto thanis incident to the flexing of a bag having thicker walls. Furthern'iore,when the flexible envelope has become impaired, it is replaced, the lifeof the rigid portions of the core being indefinite and materiallygreater than that of the rubberized fabric portion.

Although l have illustrated the preferred forms which my invention mayassume and have described in detail but a single application thereof, itwill be apparent to those skilled in the art that the invention is notso limited, but that various minor modifications and changes may be madetherein without departing from the spirit of my invention or from thescope of the appended claims.

That I claim is:

1. A vulcanizing apparatus for tire casings comprising a mold memberadapted to be disposed about theouter periphery of the casing, a rigidannular member pear-shaped in cross section adapted to be disposedwithin the tire casing, and a flexible inflatable. fluid containersubstantially crescent shaped in cross section adapted to be interposedbetween the casing and the outer periphery of the annular member, theparts being so constructed and arranged that the cusps of the flexiblecontainer are unsupported and are confined movably between the sideWalls of the casing and the annular member.

2. A vulcanizing apparatus for tire casings 'comprising a mold memberadapted to be disposed about the outer periphery of the casing, a rigidannular member pear-shaped in cross section adapted to be disposedwithin the tire casing, and a flexible inflatable fluid containersubstantially crescent shaped in cross section adapted to be. interposedbetween the casing and the outer periphery of the annularmember, theparts being so constructed and arranged that the bead portions of thetire casings are unconfned, and the cusps of the flexible container areunsupported and confined between the side walls of the casing and theannular member; whereby the stresses within the air bag are distributedand a maximum force is imposed against the inner surface of the casing.

Il. A flexible core for use in vulcanizing tire casings comprising anarcuate rubber envelope having a plurality of cords disposedtransversely thereof, a layer of square woven fabric disposed on theinner periphery thereof` and strips of diagonally disposed fabricpositioned over a. valve stem secured to the core.

4. A flexible core for use in vulcanizing tire casings comprising anannular member of crescent shaped cross section having cord fabricreinforcements disposed transversely of a rubber envelope, cross Wovenfabric disposed on the inner circumference and enclosing the cusps ofthe-envelope, a valve secured to the-envelope and fabric reinforcementsfor the valve disposed diagonally of the annular member, the entireassembly being vulcanized to form a unitary structure expansible in acircumferential direction.

In witness whereof, I have hereunto signed my name.

l RICHARD S. BURDETTE

